1. Field of the Invention
This invention relates to a method and apparatus for attaching a throttle shaft to a throttle body.
2. Related Art
Throttle valves typically include a throttle blade or disc attached to a throttle shaft, which extends across a bore formed in a throttle body. The throttle blade rotates within the bore to control air flow from an intake manifold to a vehicle engine. A pair of bearings is supported within the bore to facilitate rotation of the throttle shaft.
The assembly of the throttle shaft into the throttle body is a time consuming and labor intensive process. The bearings are installed within the bore of the throttle body and the shaft is inserted into the bore and through the bearings. To properly align the throttle disc within the bore, the shaft must be properly located with respect to the bearings and the throttle body. Typically, a distal end of the throttle shaft has a groove formed about the circumference of the shaft. Once the shaft has been inserted through the bearings, a snap ring is fitted into the groove to secure the shaft in place.
One disadvantage with this assembly process is that multiple operations are needed, which require two free hands from the assembler. This increases assembly time and cost. Thus, it is desirable to. provide a shaft attachment method and apparatus that decreases assembly time and cost, and which eliminates components resulting in improved quality characteristics.
The subject invention provides a simplified snap-fit attachment of a throttle shaft to a throttle body. The snap-fit attachment eliminates components and reduces assembly time and cost.
In a disclosed embodiment of this invention, a throttle assembly includes a throttle body having an airflow passage defining a longitudinal axis. A bore is formed within the throttle body that intersects the airflow passage and defines an axis of rotation that is transverse to the longitudinal axis. At least one bearing is supported by the throttle body within the bore and a throttle shaft is supported by the bearing. The shaft has at least one resilient cantilevered tang that retains the throttle shaft within the throttle body.
Preferably, the tang is compressed as the shaft is inserted through a central opening in the bearing. The tang is resiliently returned to a non-compressed position after the tang clears the bearing to prevent withdrawal of the shaft from the bearing.
The method of assembling the throttle shaft to the throttle body includes the following steps. At least one resilient cantilevered tang is formed on a distal end of the throttle shaft. At least one bearing is installed within a bore formed in the throttle body. The shaft is inserted through an opening in the bearing to compress the tang and the tang is resiliently returned to an extended position to prevent withdrawal of the shaft from the throttle body. Preferably, an injection molding process is used to integrally form the shaft and tang as one piece.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.